Gunnery correction device



jun@ 22, 1943. W B, KLEMPERER 2,322,455

GUNNERY CORRECTION DEVICE Filed OCT.. l5, 1940 4 Sheets-Sheet l June 22, 1943'. w. B. KLEMPRER GUNNERY CORRECTION DEVICE Filed OCt. l5, 1940 4 Sheets-Sheet 2 m 2 N 0 a d Jun@ E2, 1943.. w. B. KLEMPERER GUNNERY CORRECTION DEVICE Filed 0G12. l5, 1940 4 Sheets-Sheet 3 June 22, 1943.. W. B. KLEMPERER 2,322,455

GUNNERY CORRECTION DEVI CE Filed Oct. l5, 1940 4 Sheets-Sheet 4 atented June 22, 1943 GUNNERY CORRECTION DEVICE Wolfgang B. KlemperenLos Angeles, Calif., as-

signor to Douglas Aircraft Company, Inc., Santa Monica, Calif.

. Application October 15, 1940, Serial No. 361,213

1'1 Claims.

`vMy invention relates to gun sighting` apparatus with particular reference to a device for correcting the target lead or, in other words, a device for introducing the correction which must be alstated, there still Vremains the desirability of correcting for the target lead.

It has been proposed to obtain the parameters for this target lead correction from the angular lcwed for the component of travel of a moving 5 velocity of the tracking motions and a range target across a line of sight. nder device. However, such sources of correc- With respect to aircraft, the sighting correction .tion have several important, shortcomings. First, required in order to attain reasonable accuracy4 the range is likely to change quickly during an in hitting a moving target airplane from a movencounter between a target aircraft and a firing ing' firing airplane depends upon the relative 10 aircraft; thus the operation of a range nder motion of each craft and the inuence of air during the aiming procedure is an appreciable resistance together with the eiect of gravity burden on the gunner in addition to the acts of upon the projectile. sighting and tracking. Second, the tracking It appears to be practically impossible to obspeed can bopioked up correctly 'only providing tain all of thenecessary parameters for the coml5 the gunner succeeds inholding his sighting bead putation and construction of the complete sightactually on the target, Whenever he overtravels ing correction by merely gauging quantities physor lags behind or while he is sluing from4 one tarically or mechanically measurable aboard the rget t0 another the correction iS far fl-l Third, ing craft while training one sight upon the movthe mechanical angular velocity between the ing target end-tracking it. As a metter cf feet, movable gun and the nrine aircraft oen furnishthe only innuences that can be completely corthe Correct pick-up only provided the urine airlected by the gauging of such physically or mee craft is not maneuvering, but rather pursues ch-anically measurable quantities, are the inua straight course. Whenever the ring craft is 1 ences of the speed vector of the nring craft imturning, pitching, yawing or rolling. errors are parted to the projectile as it leaves the muzzle introduced which, unless properly eliminated. of the gun. If these phoronomic influences and SpOil the COTIGCOIL the inuences of trajectory drop due to gravity vIn order to avoid the above enumerated shortare properly introduced into a gun sight correctcomings my present invention is designed to-feed mg mechanism then there remains what has been the proper target lead correction into a sur! Sight hereinabove termed the target lead. In my co- Optical System by a method Operating 0n anellpending application, Serial No. 300,789, iiled Oc- `llilely different principle tober 23, 1939, and entitled Gun installation, I Accordingly, it isthe principal object of my have disclosed a gun mounting and sighting arinvention to feed the propertarget lead correcrangement particularly adaptable for use in a.w tion into 2- glln Sight Optical System With rea-- conned compartment :where but little room is Sonable accuracy. available for occupancy by a gunner, the inven- Another object of the invention is to easily tion being of especial utility with, but not limand Simply COIret euh sight target lead eIrOrS. lted to,the tail section, wings, and nacelles of airby a mechanism conveniently controlled by a Craftgunner as an unburdensome and natural function In that application a gun is shown mounted 40 aS he manipulates a' exibly mountedgm' i for universal movement in the tail section of an- AAnother object is to provide a mechanism for aircraft fuselage and the sight therefor is fixed in Correcting target lead errors in a xed S1111 Sight order that the gunner may sight the gun through` adapted for use with a flexibly mounted gun. its various possible movements without'moving te mechanism being mounted on and movable* his head. The nxed sight 1s equipped with a 4? Wlth respect to the gun.A ret'cule movable in the ring'eld of the gun @other obJect 1s to provide a mechanism for and connected for movement with the gun by addmg target-lead correctign to a' gun sighting a cable drive' system gliicgndcelsgned for overcoming other distortions Tlgefmnement of the dnl? system and'tre so A further object isrto .provide e device on a routhg of the cables are so deslgned vand calift b1 th hth ate brated that corrections for tangent error optical rmg mrc-m Opem e mug e m m nance l d strTm dk. f of a relative parallelism between the device and l a@ memetlo and Dhoronomi erro-rs a. target .aircraft for4 correcting target leed. are incorporated therem and reasonable accuracy A further object is to provide a, target lead 1s thereby obtained. However,v as previously 55 4correction device adapted to introduce any comsighting mechanism through translational, rotative and otherwise universal movement of the device by a gunner as gaugei 'from' the velocity and aspect of a moving target. I

Other and further objects will become apparent after a reading of the following description and a study of the drawings in which: Figure l is a` side elevation showing an embodiment of my present invention as adapted for use on the gun installation disclosed in my copending application previously set forth, a gunner being shown in phantom and in a normal position for concurrent manipulation'of my target lead correction device and a gun. Figure 2'is a perspective view of the butt portion of a machine gun and showing the installation of my target lead correction device thereon, the device replacing one of the conventional spade grips of the gun.

Figure 3 is a perspective view of a ixed gun f sight incorporating a movable reticule together` with a cable and drum mechanism for 'imparting horizontal movement to the reticule-in response to horizontal movement of la gun and showing points of connection for my target lead correction device.

Figure 4 is a perspective view of the fixed gun sight of Figure 3 together with the movable reticule and .a cable and drum mechanism for imparting vertical movement to the reticule in response to vertical movement of a gun and showing points of connection for my target lead correction device.

Figure 5 is a front elevational view of the movable reticule' portion of the fixed gun sight with the cover thereof removed and showing the horizontal and vertical adjustment cable drums,

In Figure 1 I have shown the primary essenltials 'of the invention'v as installed on a gun which is mounted in the tail section of an aircraft for limited flexibility, for example, to fire hr a 60 cone.

asesinos y bination of correction componentsinto a gun A gunner v26 is shown in phant'cn in Figure 1 and for his use in aiming the gun I 6,. a xed telescopicgun sight assemblyl 30' is mounted in .a position above the gun in a manner such that the field piece 32 thereof is directed toward the-areaor field' lying to the rear of the tail of the aircraft. The cone space of the anlgular field of the telescopic-gun sight 30 covers slightly more than the field in which the gun may be aimed and fired, thereby making it possible to fire the gun at any point or target which may be brought by the gun' sight 30 to the eye of the gunner. f The gun sight essentially comprises a complement of optical lenses including an eyepiece lens system in the eyepiece 34, and also an objective lens system in the ii'eld piece 32, with suitable erecting lenses disposed therebetween.

dPreferably the lenses of the gun sight 30 are enclosed by a suitable housing such as the tubular structure 36 attached to the aircraft structure by meansof brackets 38 and 4I. A reticule box 40 is shown disposed adjacent to the eye piece of the gun sight 30. Within the reticule box a reticule is movably mounted so that it may move in or parallel to the focal plane of the eyepiece.' Means are provided, as hereinafter described, for moving the reticulel so that it will appear in the visual image which passes to the eye of the gunner, in a position to indicate the point in th-e field at, which the gun may be aimed at any time.

As shown by Figure 5, the reticule 42 isycarried by a reticule frame 44, which is supported in the box 40. One portion of thisv frame projects into a horizontalframe 46 in a mannerto slide The outline of the tail portion of the aircraft is indicated by the numeral I0 and an opening I2 is provided in the right or aft end thereof for the projection of a muzzle I4 of a vgun I 6 therethrough. Doors or other closure means may or may not be provided to fair in this opening as deemed advisable but inasmuch as that is no feature of my present invention alldetails with respect thereto have been omitted. The only refquirement with respect to the opening I2 and closure means therefor is that they shall permit suicient movement of the gun muzzle to cover the desired conal field of fire.

The gun I6 is mounted for limited universal movement in a yoke I8 .which is in turn attached tothe aircraft tail structure I0 by vmeans of -a Vbracket 20.- 'I'he lower portion of-`the yoke is .iournaled tothe bracket at 22 for rotative movement about a vertical axis. The gun itself is journaled to the yoke at 24 for rotative movement about a horizontal axis.

i Normally, a conventional machine gun is equipped with a right and left hand spade grip "iat," the butt end thereof to be grasped bythe gunner for swinging the gun.j} However, in this invention, the right hand spadeqgrip has been replaced by my target llead correction device, leaving'only a left hand grip 26 as shown in Figure 2. Thus, when moving the gun the gunner grasps the grip 26 with his left hand and manipulates the correction hand.

device withlns right horizontally between the upper and lower bars 48 thereof.y Another portion of the frame 44 projects into a vertically elongated 4frame 50 in a manner; to be slidable vertically along the bars 52 of such frame.- The horizontally elongated frame is engaged by a vertical right-handy 'threadedscrew'54 so afs to be moved vertically in either direction from 'the position in which .r it is shown in the drawing. A horizontal lefthand threaded screw 56 engages the vertically l elongated frame and may be operated to move systems 66 and 68; cable system 66. shown in 1 Figure 3, tying'in with drum the frame horizontally in either direction from the centralized position thereof shown in the drawing. These screws 54 and 56 are supported bysuitable anti-friction bearings 58 and 60 so as to project within thebox. It will be seen that whenthe screw 54 is rotated, vertical movement of the frame 46 will move the reticule frame in vertical direction and such' reticule frame 1 will Yslide along the vertical bars 52. When the screw, 56 is rotated, the vertically elongated frame 50 will move the reticule frame 44 along the horizontal bars 48 of the frame 46. Accordingiy, by operation of screw 54 or screw 56 the reticule 42 may be moved either vertically or horizontally, or by a simultaneous rotation of thescrews 54, 56'the reticule may be moved in any angular direction between vertical, and hori- 4 zontal. l

In -order to provide means for rotating the screws 54, 56 in accordance with the vertical and horizontal components of the movement of the gun I6, cable drums 62 and 64 are fixed to the exposed ends of the screws 54 and 56. The drums are then woundby cables from individual cable 62; and cable system 68, shown in Figure 4, tying in with drum 64, Eachcable system includes a plurality of Y' pulleys and a driving drum, the vlatter being rotated in response to movement of the gun I6.

For example, 'the driving drum 'l0 of cable system 68 may be mounted on the gun yoke |8 somewhat on the order of the showing of Figure l and geared in a suitable manner as shown in Figure 3 to rotate in response to horizontal movement of the gun. On the other hand, the driving drum 'l2 of cable system 68 may be mounted on the side of the gun yoke I8, as shown in Figure 1, and also geared in a suitable manner as shown in Figure 4 to rotate in response to vertical movement of the gun.

The routing of the cable systems, contour pf the cable drums and gearing of the driving drums are necessarily designed and calibrated to impart movement of the reticule 42 corresponding to movement of the gun IB and to introduce the required corrections therein for tangent error, distortion and kinematic and phoronomic erre "s. A disclosure of the details and problems conn-acted with this design and calibration has been included in my co-'pending application and it has been my purpose here to` repeat only such details of my previous invention as are necessary to afford a clear understanding of the present invention.

Accordingly, I will now explain the features and operation of the new device as it may be incorporated with .the previous invention.

It has been mentioned that it is proposed to install the target lead correction control on the butt end of the machine gun I6 in place of the right hand spade grip. 'I'his is best shown in Figure 2 wherein 'a g'imbal ring 80 is pivoted for rotation on a vertical taxis between a pair of brackets 8| extending fromthe gun i6. Within the ring 80, through the center thereof, is placed what may be termed a vector handle 82 and this handle is mounted for rotation in an elongated rthreaded colla 84. The collar is in turn pivoted to the ring 80 on a pair of stub shafts 88 which lie in a position normal to the vertical rotative axis' of the ring.

The handle 82 is shaped on the order of a pencil and, by its mounting, it is capable of universal articulation. A portion of the handle is provided with a long pitch screw thread at 88 in order that it may be rotated `by the gunner and thus caused to move fore and aft with re-l spect to its correspondingly threaded mounting collar 84|. Toward the left end of the handle, that which is grasped by the gunners hand, a

small excresence or iinger 90 is provided which will indicate to the hand the amount in which the handle has been turned on its screw thread.

On the right end of the handle 82 there is universally pivotally mounted a button shaped 4itting 82 to afford attachment-for cables 94,

88, 88, |00 at perpendicular diametrically opposite points on the periphery of the button. 'I'he cables are of the Bowden type adapted to extend through casings |02, |04, |06, A|08 respectively. The casings are fixed to the butt of the gun H5, being held in proper positions with respect to the button fitting 92 by a bracket |||l bolted to the gun butt at ||2 and a bracket The cables extend from the fixed attachments on the gun to fixed attachments on the tail structure I0 of the aircraft. These fixed` structural attachments are indicated by the brackets ||4 and IIB in Figure 3 and the brackets ||8 and |20 of Figure 4. VAn ample allowance of slack cable is allowed between vthe gun and structural 'attaching points in order to permit the required movement of the gun I6 on its horizontal and vertical axes. f

Referring now to Figure 3, continuation of the Bowden cables 94 andv 96 of Figurev 2 are shown as they tie in-to the reticule driving cable system 66. Cable 94, after passing the structural casing attachment bracket I I4, terminates at |22 in-one end of a clevis-type-pulley carrier |23 in which are fixed the axle shaft |24 of a oating pulley |26, and the axle shaft |30 of a float- A ing pulley |32.4 Cable 96, after passing the strucwhich are afxed the axle shaft |38 of 'a floatxed tobracket 8| at H3. The bracket ||0, in

the embodiment shown, attachesJto one side of the gun and has a plurality of arms for supporting casings |04, |08, and |08. Bracket supports casing |02. Each of the supporting means is disposed so that the casing held thereby is routed in a manner to assure the absence of binding.

tural casing attachment bracket IIB terminates at |28 .in theother end of the pulley carrier. The routing of the Bowden cables is such that they 4approach each other in the same plane from opposite directions. The two oating pulleys |26 and |32 are secured in fixed relation to eachother by the pulley carrier |23 which holds them spaced from one another..

With reference to Figure 4, the continuation of thev Bowden cables 98 and |00 of Figure 2 is almost identical with that just described for cables 94 andY 96. In Figure 4 they are shown as they tie into the reticule driving cable system 68. Cable 98, after passing the structural casing attachment bracket |20, terminates at |36 in one end of a clevis-type pulleyV carrier |42 in ing pulley |40, and the axle shaft |44 of a oating pulley |46. Cable |00, after passing. the structural casing attachment bracket I8, termi-v nates at |45 in the other end of the pulley carrier. The routing of the Bowden cables, as be- -fore, is such that they approach each other in the same` plane from opposite directions. These two oating pulleys |40 and |46 are also secured in xed relation to each other by the pulley carrier |42 which holds them spaced from one another. f

Thus far, I have described the component parts of my target lead correcting device which coopcrate to influence the reticule driving cable systems 66 and 68. I will now discuss the operation of these parts as controlled by the gunner 28 to obtain target' lead correction as he sights and manipulates the gun I6.

The gunner grasps the left portion of the. pencil shaped handle 82 .with his right hand in a similar manner to that shown in Figure l, and grasps the spade grip 26 of the gun with his left hand in order to move the gun about. If he permits the handle 82 to remain in its neutral position shown no movement will take place in the Bowden cables, the slack mentioned between the gun and tail structure attachment points permitting. unhampered movement of the gun. If he displaces the handle from its neutral position however, a displacement of the cables will take place which will react on one or the other or both cable systems 66, 68, depending upon which way the handle 82 is moved. For example, if the gunner raises his end of the handle, the opposite reticule '42' inasmuch as movement of the floating pulleys relative to the cable system driving drum 12 will causea slight rotation of the reticule cable drum 64.

Similarly, any movement of the handle 82o from neutral will displace one or more of the cables depending upon the direction of motion and will cause a movement of the reticule in addition to that normally imparted thereto by the driving drums and 12.

In order to produce an excursion proportionate to the target speed component for various target air speeds I 'provide a variable leverage of the Bowden cable pick-up point 92 with respect to the universal joint axes 8B. The larger this leverage, the greater the movement of the pickup point for any given angular displacement of the handle 82. Adjustment of this leverage is accomplished by rotating the handle 82 about its longitudinal axis in clockwise or counterclockwise direction so that -by virtue of its long spiral thread 88 it moves in or out. With the handle withdrawn to its limits the device is adjusted for minimum target air speed. With the handle screwed fully in the leverage is maximum and the device is adjusted for the maximum anticipated target air speed. It must be understood that the end brackets of the Bowden cable must be sufficiently far away from the drum fitting 92- that the latters movement around an arc or aroundthe axis of the handle will not cause excessive length variation in the two opposing cables attached to the drum or else suitable measures must be provided to control the average cable tension.

In combat operation, the gunner sights his target in the telescope 30, then, assuming that he is aiming at a moving target airplane he manipulates the handle 82 of the target speed correction device so that its direction appears parallel to the direction of motion of the target craft.

Tests have shown that but little practice will be required for the gunner to become adept at dlrecting the handle, moving it continuously so that it feels parallel to the fuselage of the targetv craft as the latter appears in the field of vision, without having to glance at the handle. The accuracy of parallelism may be somewhat limited by feel and estimate but the rst order target speed influence can readily be represented.

-The universal mounting of the handle 82 is preferably such that movement of the handle is limited to a reasonable cone with respect to the member upon which the device is mounted. The arrangement must merely suflice to cover the most important combat configurations in which the target crafts path makes a. moderate angle with either the flight path of the firing craft or the sighting line as the case may be. For such a limited firing cone it appears satisfactory to mount the device in place of one of the spade grips as shown in Figures 1 and 2. For gun installations in. rotatable turrets sweeping large spherical angles and equipped with gun sights embodying periscopic features, it may be preferable to support the fulcrum of the articulated handle on' the turret structure rather than mounted directly on the gun.

The forward and aft movement of the handle 82 is, as stated, for the purpose of-reproducing estimated' changes in the target crafts air speed. In order to obtain the proper correction, it is necessary that the button fitting 92 to which the `Bowden cables attach be located at a distance from the universal mounting of the handle which is proportional to the target air speed, then the excursion of the pick-up point of the cables on the button fitting with respect to the handle axis is always directly proportional to the proper target lead correction for any target moving through the air parallel to the longitudinal axis of the handle.

The small excresence or nger 90 on the handle 82 serves as a pointer indicating the speed to which the device is set. As the gunner rotates the handle clockwise the little finger 90 in moving through approximately one complete revolution would represent an adjustment of the target speed value from, say, two hundred to four hundred miles per hour. Thus the speed adjustment can be made with one hand by feel only without having to look at the handle. The target speed, to be sure, has to be estimated by the gunner knowing the target crafts and his own speed approximately. However, he should have no difculty in at least hitting the proper order of magnitude, as he perceives in the gun sight whether the target is gaining or falling back with respect to his own craft.

As the handle 82 is manipulated, the horizontal Bowdeny cables 94 and 96 will pick up the first order component of the horizontal excursion of the button fitting 92 and the vertical Bowden cables 98 and |00 will pick-up the corresponding vertical excursion component. The influence of the Bowden cables upon the reticule mechanism through the loose pulley arrangement remains unchanged for any xed position of the target speed correction device. Any correction dictated by the device is added toor substracted from the'reticule movement introduced by the gun swivel mechanism through the drive pulleys 10, 12.

In order to further simplify the gunners job, it is possible to relieve him of automatic variation of the target crafts speed with the 'attitude of the target craft. The craft will gain speed as it dives and lose speed as it climbs. A first order correction for this influence can be calculated and obtained by placing the vertical Bowden cable anchorage at some angle with the night axis of the ha'ndle 82, or by rocking the gimbal ring in which the handle is mounted on a cam cradle.

While I have herein shown and described my invention in its present preferred embodiment, it will be apparent to those skilled in the art to which it appertains that the essence of the lnvention lies in influencing, in accordance with the estimated speed vect0r of the target,- the sighting indication to the gunner so that it is moved out of synkinesis with the travel of the gun in the field of re in the approximate amount necessary to introduce correction to compensate for target lead. Accordingly, after understanding the invention, various changes and modifications may be made therein without departing from the scope thereof as set forth in the appended claims.

The word "synkinesis is used herein to describe that relationship between the movements of two bodies characterized by a constant relative position of a significant character. Thus the reticule movement is in synkinesis with the gun movement when the reticule indicates on the visual image of the sight the point at which the gun is aimed wherever the gun 4is directionally moved. The word ecsynkinetize, as used in connectionwith a previously specified synkinesis, is a word coined to describe the act of effecting a new relationship of movement between two bodies previously in synkinesis of a specied character which is not characterized by that synkinesis. I claim:

1. In a correction device for use on a militaryvehicle, a gun sight fixed to said vehicle, a movable gun, a reticule movable by aiming movements of the gun relative to the optical axis of the fixed gun sight for indicating to a gunner the point at which the gun is aiming in its field of lire, mechanism connecting the reticule to the gun for synkinetized movement therewith, and extraneous means connected to the reticule moving mechanism and operable by the gunner in accordance with the direction of relative target motion to ecsynkinetize movement of the reticule with respect to the gun as the gun traverses its field of re.

2. In a correction device for use on a military vehicle, a gun sight fixed to said vehicle, a movable gun, a reticule associated with the fixed gun sight and movable by aiming movements of the gun relative to the optical axis of the fixed gun sight for indicating t a gunner the point at which the gun is aiming in its eld of fire, mechanism connecting the reticule to the gun for movement therewith, a universally movable handle adapted to be grasped by the gunner and manipulated in a manner such that its 1ongitudinal axis is maintained substantially parallel to the direction of motion of a target, and means connecting said handle and said mechanism whereby any movement of the handle adds to or subtracts from the normal movement of the mechanism eiected by movement of the gun.

3. In a correction device for use on a military vehicle, a gun sight fixed to said vehicle, a mo'vable gun, means within'l the fixed sight movable relative to the opticalzsight axis by 'aiming movements of the gun for indicating to a gunner the point at which the gun is aimingin its field of nre; a single universally fulcrumed handle| mounted for movement with the gun and with respect thereto, said handle being adapted to be manipulated in a manner such that its longitudinal axis is maintained substantially parallel to the direction of motion of a target in the guns` eld of iire, means to transmit movement from said handle to said indicating means extraneous of the movement eiected by said gun, and

gimbal for universal movement about the fulcrum and for axial movement with respect thereto, articulated means attached to one end of said handle, and mechanism connected to said articulated means and to said movable means within the iixed sight for transmitting motion to said movable means in response to any displacement o f said universally mounted member both with said gun and with respect thereto.

6. In an aircraft having a movable gun, a gun sight including an optical system fixed in said aircraft, a horizontally sliding means and a vertically sliding means mounted within said xed gun sight, a'reticule movable in a plurality of directions Within said two, sliding means as controlledfby relative movement of said two sliding means, means to move said horizontally sliding means in correlation with azimuthal movement of the gun, means to move said vertically sliding means in correlation with elevational movement of the gun, and means to introduce sighting corrections between the movement of the gun and v the `movement of said horizontally and vertically means for changing the position of said handle v with respect to its fulcrum to increase or de-;

crease its degree of inuence upon the indicating means in accordance with the estimated velocity of the target.

fl. In a correction device for use 0n a militaril vehicle, a gun sight fixed to said vehicle, a mov-i able gun, means within the fixed sight movable relative to the optical sight axis by aiming movements of the gun for indicating to a gunner the point at which the gun is aiming in its eld of nre, and a single means universally swingable about a pivot for moving the first named means out of synkiness with the gun and movable axially with respect to its pivot to vary the degree of inuence exerted over the rst named means in accordance with the estimated velocity of a target at which the gunner is aiming.

5. In a correction device for use in conjunction with a iixed gun sight and a movable gun, means within the xed sight movable by the gun relative to the optical sight axis for indicating to a gunner the point at which the gun is aiming in its eld of fire, a gimbal mounted on said.

gun, a handle mounted on a fulcrum in said sliding means, said correction introducing means including a manually controlled universally articulated lever adapted to be manipulated parallel in space to the path of a moving target as seen through said optical system.

7. In an aircraft having a movable gun, a gun sight including an optical system fixed in said aircraft, a horizontally sliding means and a vertically sliding means mounted within said fixed gun sight, a reticule movable in a plurality of directions within said two sliding means as controlled by relative movement of said two sliding means, means to move said horizontally sliding means in correlation with azimuthal movement of the gun, means to move said vertically sliding means in correlation with elevational movement of the gun, means to introduce sighting corrections between the movement of the gun and the movement of said horizontally and vertically sliding means, said correction introducing means including a manually controlled universally articulated lever adapted to be manipulated parallel in space to the path of a moving target as seen through said optical system. and means associated with said lever to vary the amount of introduced-correction in accordance with the estimated air speed oi the target.

8. In an aircraft having a movable gun, a gun sight including an optical system xed in said aircraft, a horizontally sliding means and a vertically sliding means mounted within said fixed gun sight, a reticule movable in a plurality of directions within said two sliding means as controlled by relative movement of said two sliding means, means to move said horizontally sliding means in correlation with azimuthal movement. of the gun, means to move-said vertically slidingmeans in correlation with elevational movement of the gun, means to introduce sighting corrections between the movement of the gun and the movement of said horizontally and vertically sliding means, said correction introducing means including a lever pivoted to said gun for movement both with and with respect thereto, said movement with respect thereto being always parallel to the direction of movement of a target as viewed in said fixed gun sight, a cable System interconnecting said lever with each of said gun sight sliding means for imparting additional movement to either or both of said means in accordance with the movement of said target, and means for changing the position of said lever with respect to its pivot to vary in accordance with the estimated target speed -the degree of additional movement originally imparted to said sliding means.

of the reticule as to indicate to the gunner the point at which the gun is aiming'in its .field of iire, means modifying the action of ,said energy transmitting means to give to thereticule a displacement in any/direction with respect to the positions of said synlrinesis, and a manual operating controlfor said modifying means comprising a member capable oi being universally directionally displaced from a neutral directional position with reference to the gun to maintain the member in estimated parallelism with the direction of relative movement of the target, said modifying means being controlled by said member to effect said reticule displacement in the opposite direction from that of the said displacement of said member and of a magnitude havin! a direct substantially factoral relation to that of the langle of said directional displacement of said member from said neutral position.

1o. The combination cleaned in claim 9 'and in addition thereto means under the control of the gunner for 'adjusting said modifying means to vary the factor of said relationship to compensate for the estimated Vspeed of said moving target. Y

1l. In a correction device for use on a military vehicle, a gun sight xed to said vehicle, a movable gun, means within the xed sight movable relative to lthe optical sight axis by aiming movements of the gun for indicating to a gunner the point at which the gun is aiming in its field of iire, a member mounted on said gun for universal directional movement relative thereto,'articulated means attached to one lend of said member, and mechanism connected to said articulated means and to said movable means within the fixed sight for transmitting motion to said movable means in response to 'any directional displacement of said universally mounted member WOLFGAN G B. 

